The tier system

Ports are classified into three tiers based on the current
importance of the architecture and the level of community
activity. Summarizing, the tiers can be viewed to
represent ports that NetBSD will support, ports that
NetBSD does its best to support, and ports which may be
desupported soon. The tier for each port may change over
time and is decided by <core@NetBSD.org>
based on input from users and developers.

More exact guidelines for tiers along
with the port taxonomy is presented below.

Tiers

Tier I: Focus — support is part of NetBSD's strategy

Focus ports are the architectures that NetBSD targets as
part of its strategy. The platforms consist of modern
server, embedded and desktop architectures.
The guidelines are as follows:

Machine independent (MI) changes should benefit these ports.

MI changes must be tested on at least one of these ports.

It is the developer's responsibility to implement machine
dependent (MD) support necessary for changes, fix build problems
and aid in debugging with any platform-specific problems.

Even within a port, common sense should be used
(cf. the i386 port which still supports 486).

Regressions in the automated NetBSD test suite (/usr/tests)
are not allowed.

Tier II: Organic — evolving at its own pace

Organic ports are highly valued by the NetBSD project,
but their development is not as tightly mandated as that
of the focus ports. Generally speaking, the hardware
platforms of organic ports have lost their industrial
relevance, or there is not enough community activity for
the port to make it to the first tier.
The guidelines are as follows:

Generally speaking, the port boots and works, but keeping
it working is the responsibility of the user community.
This includes, but is not limited to, kernel changes
and toolchain upgrades.

Developers committing MI changes are still encouraged to
keep ports up-to-date when it can be easily done.

MI architecture decisions may penalize organic ports if
there is a benefit for focus ports.

If the port is not working at release time, a release is
done without the port and the port is moved down to the
life support tier.

Tier III: Life Support — severely incapacitated or broken

Ports are moved to life support if they no longer function.
The reasons can range from lack of community interest to
the hardware becoming so rare that it is simply not
available any more. If ports in life support are not
shown to be working within a reasonable timeframe, they
will be moved to the Attic. The guidelines are as follows:

Organic ports get moved here if they do not complete a build
for 6 months or are otherwise suspected to be broken.

It is the responsibility of the users of an organic port to show
it is working, not the other way around.

Movement to life support causes a mail to be sent out to the port
mailing list and the portmaster.

Port will be bumped up to organic when it is shown to be working.

If the port is not reported fixed within the next 6-12 months,
it will be moved to the Attic.

CPU architectures

Ports by CPU architecture

This table contains the same set of ports as in the above list,
but ordered by MACHINE_ARCH CPU architecture value (returned by
'uname -p') and showing a total of
16
CPU types. Machines of the same MACHINE_ARCH share the same
userland binaries (with a few device specific exceptions).
Both big endian (eb) and little endian (el) MIPS and SH3
ports are supported.